package org.bouncycastle.asn1.x509;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERIA5String;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DERSequence;

/**
 * Policy qualifiers, used in the X509V3 CertificatePolicies extension.
 * 
 * <pre>
 *   PolicyQualifierInfo ::= SEQUENCE {
 *       policyQualifierId  PolicyQualifierId,
 *       qualifier          ANY DEFINED BY policyQualifierId }
 * </pre>
 */
public class PolicyQualifierInfo extends ASN1Encodable {
    private DERObjectIdentifier policyQualifierId;
    private DEREncodable qualifier;

    /**
     * Creates a new <code>PolicyQualifierInfo</code> instance.
     * 
     * @param policyQualifierId
     *            a <code>PolicyQualifierId</code> value
     * @param qualifier
     *            the qualifier, defined by the above field.
     */
    public PolicyQualifierInfo(DERObjectIdentifier policyQualifierId, DEREncodable qualifier) {
        this.policyQualifierId = policyQualifierId;
        this.qualifier = qualifier;
    }

    /**
     * Creates a new <code>PolicyQualifierInfo</code> containing a cPSuri qualifier.
     * 
     * @param cps
     *            the CPS (certification practice statement) uri as a <code>String</code>.
     */
    public PolicyQualifierInfo(String cps) {
        policyQualifierId = PolicyQualifierId.id_qt_cps;
        qualifier = new DERIA5String(cps);
    }

    /**
     * Creates a new <code>PolicyQualifierInfo</code> instance.
     * 
     * @param as
     *            <code>PolicyQualifierInfo</code> X509 structure encoded as an ASN1Sequence.
     */
    public PolicyQualifierInfo(ASN1Sequence as) {
        if (as.size() != 2) {
            throw new IllegalArgumentException("Bad sequence size: " + as.size());
        }

        policyQualifierId = DERObjectIdentifier.getInstance(as.getObjectAt(0));
        qualifier = as.getObjectAt(1);
    }

    public static PolicyQualifierInfo getInstance(Object as) {
        if (as instanceof PolicyQualifierInfo) {
            return (PolicyQualifierInfo) as;
        } else if (as instanceof ASN1Sequence) {
            return new PolicyQualifierInfo((ASN1Sequence) as);
        }

        throw new IllegalArgumentException("unknown object in getInstance.");
    }

    public DERObjectIdentifier getPolicyQualifierId() {
        return policyQualifierId;
    }

    public DEREncodable getQualifier() {
        return qualifier;
    }

    /**
     * Returns a DER-encodable representation of this instance.
     * 
     * @return a <code>DERObject</code> value
     */
    public DERObject toASN1Object() {
        ASN1EncodableVector dev = new ASN1EncodableVector();
        dev.add(policyQualifierId);
        dev.add(qualifier);

        return new DERSequence(dev);
    }
}
